Chemical Oceanography Ryan Lecture 10 - April 15, …faculty.uml.edu/david_ryan/84.653/Course Material...1 Chemical Oceanography Organics III Dr. David K. Ryan Department of Chemistry

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ChemicalOceanographyOrganics III

Dr. David K. RyanDepartment of ChemistryUniversity of Massachusetts Lowell&Intercampus Marine Science (IMS) Program

http://faculty.uml.edu/david_ryan/84.653

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Humification ofOrganic Matter(possible scheme)

Libes, 1992

Hydrocarbons, Fats, WaxesOils, Sterols, Vitamins, etc.

Biotic

Abiotic

Macromoloecules

aggregationagglomeration

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Humification ofOrganic Matter(another scheme)

Libes, 1992

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Emerson & Hedges Figure 8.2

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Morel & Hering,1993See also Emerson & HedgesFigure 8.11 & 8.12

6Humic Structure Proposed by Schnitzer (Rashid 1985)

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Structure Attributed to Gamble et al. (1985)

8Morel & Hering (1993) Based on Aiken et al. (1985)

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Possible StructuralUnits Set Forth byAverett, Leenheer,McKnight & Thorn(1989) From Morel& Hering, 1993

10Kleinhempel reprinted from Albrecht Thaer Archiv (1970)

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Organic Solute Macromolecule (ORSMAC) Leenheer 1985)

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Davies & Ghabbour, 1999

Carbon atoms-greenOxygen atoms-redNitrogen-blueHydrogen not shown

Molecular model of the lowestenergy conformation ofhumic acid building blocks

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluenceBind Metals & Organic PollutantsTerminal Electron Transport Acceptor for Bacteria

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Sea Foam caused by naturally occuring surface active agents

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Air-Sea Interfacial Chemistry

Surface active compoundsconcentrated at interface

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluenceBind Metals & Organic PollutantsTerminal Electron Transport Acceptor for Bacteria

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Fox, 1983

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluenceBind Metals & Organic PollutantsTerminal Electron Transport Acceptor for Bacteria

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Millero, 1996

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CDOM = Chomophoric (or Colored) Dissolved Organic Matter

Photochemistry

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluenceBind Metals & Organic PollutantsTerminal Electron Transport Acceptor for Bacteria

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Quinone radicalpresent in humic material

Scott, McKnight, Blunt-Harris, Kolesar & Lovely (1998) Environ. Sci. Technol. 32, 19

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluence TransportBind Metals & Organic PollutantsTerminal Electron Acceptor for Bacteria

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Humics involved in many reduction reactions

Cr(IV) to Cr(III)Fe(III) to Fe(II)Hg(II) to Hgo

As, Se and V species

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluence TransportBind Metals & Organic PollutantsTerminal Electron Acceptor for Bacteria

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Metal Complexationby Humic Materials

Leenheer et al. (1998)Morel (1983)

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluence TransportBind Metals & Organic PollutantsTerminal Electron Acceptor for Bacteria

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Humic material will aggregate & may“salt out” when it binds a cation

Leenheer, J.A. et al. (1998) Environ. Sci. Technol. 32, 2410

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Importance of Humic MaterialsGlobal Carbon ReservoirTake Part in Interfacial PhenomenaUndergo Coagulation and AggregationInvolved in Photochemical ReactionsContain RadicalsKnown Reducing AgentsMethylate MetalsForm Chlorinated Species, THMs DBPsDetoxify MetalsLimit Bioavailability of MetalsAlter SolubilityInfluence TransportBind Metals & Organic PollutantsTerminal Electron Acceptor for Bacteria

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Maturation and Fossilization are terms that refer to the formation of fossil fuels (coal, petroleum) from plant and animal material (biomolecules).The overall process can be split into two or three

major parts:Marine Diagenesis, Catagenesis, MetagenesisTerrestrial Humification, Coalification

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FossilizationPathway of theCarbon CycleHartenstein, 1981Van Krevelen plot

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from Hartenstein, 1981

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Libes, 1992 “…diagenetic changes …occur under anoxic conditions at temperatures less than 50 oC.”

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Sediment Diagenesis includes more thanOrganic Matter Transformations – Many redox processes occur

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Libes, 1992

PetroleumMaturationProcess

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Libes,1992

Evolutionof FossilFuels

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Morel & Hering,1993